Dating a Japanese Girl

I'm a caucasion American in college and my new girlfriend is Japanese -- she's here for college and has been here about 5 years. I made her my girlfriend but neither of us are really sure what that means. Anyway I like her and I'm pretty sure she likes me, but she's very cautious when it comes to relationships. I think this has to do with her being a traditional Japanese girl. So, to make a long story short, she always wants to spend time with me but I can't get physical with her at all. I'm embarrassed to say that after 3 weeks of dating the most I've done was kiss her on the cheek. Am I wrong for wanting too much too soon?

The thing is, she is a quality girl and I like that - I could dump her and get a girl who would be easier, but she wouldn't be of the same pedigree. But the problem is I can't let this go on forever and I don't want a platonic relationship.

Any general advice or information on Japanese customs would be appreciated. I'll post more details upon request.